16. Which of the following statements concerning alveoli wouldbe correct? SELECT ALL THAT APPLY!!
a. Pulmonary surfactant of the alveoli is secreted by Type IIalveolar cells.
b. When intra-alveolar pressure becomes greater than atmosphericpressure expiration will occur.
c. The walls of the alveoli are very thin and are surrounded bya network of capillaries so that air and blood are separated byonly a very thin respiratory membrane.
d. Alveoli are the site of gas exchange in the lungs. e. Thewall of the alveoli is composed primarily of simple squamousepithelium.
